Electromagnetic stepping device



July 14, 1959 H, p L c 2,895,091

ELECTROMAGNETIC STEPP ING DEVICE Filed Feb. 18, 1957 i4 FIG.|

INVENTOR JACOB H. DRILL ICK ATTORNEY United States Patent 2,895,091 ELECTROMAGNETIC srsrrnsc nnvrcn Jacob H. Drillick, Orange, N.J., assignor to Monroe Calculating Machine Company, Orange, N.J., a corporation of Delaware Application February 18, 1957, Serial No. 640,773 9 Claims. (Cl. 317-192) This invention relates to stepping devices and particularly to such devices which are electromagnetically operated and which have a number of utilities such as, for example, the control of switching means, counting and indicating operations, etc.

The principal object of the invention is to provide an electromagnetically operated stepping device which is simple in construction and which is capable of high speed positive operation.

A further object of the invention is to construct such a stepping device having a minimum number of moving arts.

p Other objects and advantageous features of the invention will be evident hereinafter in consideration of the detailed description.

To accomplish the above objects, the stepping device includes only one moving part which consists of an armature. In response to each pulse from an electrical pulse source, the armature is first operated electromagnetically against a spring bias and then operated by the spring bias. In each of these operations, guide means is employed to control the armature in stepwise movement. The invention, however, will best be understood from the following description of a preferred embodiment with reference to the accompanying drawings in which:

Fig. l is a longitudinal section of the steppingdevice taken on line 11 of Fig. 2.

Fig. 2 is a left end view of the device.

Fig. 3 is a section taken on line 3-3 of Fig. 1.

Fig. 4 is a fragmentary right end view of the armature mounting means.

Fig. 5 is an enlarged fragmentary view of the armature guide members.

The electromagnetic stepping device comprises a cylindrical casing of magnetic material such as iron, and des-' ignated generally by the reference numeral 1. An inner cylindrical bore 2 (Fig. 1) extends longitudinally from the right end wall 3 of the casing and connects with an enlarged cylindrical bore 4. Bore 4 extends longitudinally toward the left end of casing 1 and connects with the internally threaded end portion 5. Means for linking the magnetic circuit, later described, comprises a solenoid coil 7 which is contained within casing 1 at the right end of bore 2 and which is provided with a central axially extending opening 8.

An armature which comprises a length of wire 10 of resilient magnetic material such as piano wire is fixedly mounted at one end at the center of end 3 of casing 1. The mounting means for wire 10 comprises a tapered split clamping sleeve 11 (Figs. 1, 4) of magnetic mate rial'which is wedged in a longitudinally extending tapered opening of a threaded bolt 12 of magnetic material which is threaded concentrically through end wall 3 and retained in threaded position by a lock nut 13. Armature wire 10 extends through opening 8 of coil 7 toward the left end (Fig. 1) .of cylinder 1 and is there controlled in its movement by guide means later described.

The guide means for armature 10 comprises outer and 'ice inner guide members 14 and 15 respectively of non magnetic material such as brass and concentrically mounted in casing 1. Outer guide member 14 is ring shaped and located in bore 4 of casing 1 with its right end face engaging a ring 16 of magnetic iron which is contained at the right end of said bore. The right end (Fig. 1) of guide member 14 comprises an annulus of internal guide teeth 17. The root or outer diameter of guide teeth 17 is coincident with the inner diameter of magnetic ring 16 which is non-integral with magnetic casing 1 only for purposes of assembly. The clockwise side 17a (Figs. 3, 5) of each tooth 17 of guide member 14 provides a guide surface for armature 10 and the adjoining counterclockwise side 17b of the next tooth 17 provides an abutment or stop face for said armature.

At the left end (Figs. 1, 2) of outer guide member 14 is a cylindrical concentric bore 14a into which is fitted a disc 18 of dielectric material such as Bakelite. A pin 19 engages a slot at the periphery of disc 18 and extends toward the right into an opening in guide member 14 thereby fixing said guide member and discs 18 in circumferential angular relationship.

Inner guide member 15 is in the form of a hub axially mounted with respect to disc 18 on its right face (Fig. 1). Means for securing guide member 15 comprises a threaded integral stud 20 extending toward the left through an opening in said disc 18 and engaged by a clamping nut 21. A pin 22 engages openings in guide member 15 and disc 18. Consequently, a fixed angular relationship is maintained between inner guide member 15 and outer guide member 14 which, as described, is angularly fixed with respect to disc 18. The assembled unit comprising guide members 14, 15 and dielectric disc 18 is retained in bore 4 of easing 1 by a brass clamping ring 23 which is threaded in end 5 of said casing and engages the left face of disc 18.

Inner guide member 15 comprises a circumference of outer guide teeth 24 which are 'complementally operable with respective guide teeth 17 of the outer guide member 14 as later described. Guide teeth 24 are spaced radially inward from teeth 17 and the clockwise side 24a (Figs. 3-5) of each tooth provides a guide surface for armature 10 whereas the counterclockwise side 24b provides a stop face. The left free end (Fig. 1) of armature wire 10 extends between the opening defined by outer guide teeth 17 and inner guide teeth 24. Armature wire 10 is resiliently biased toward a straightened axially aligned position with respect to casing 1 and concentric guide members 14 and '15. The armature therefore will normally engage a root of a pair of inner guide teeth 24 defined by a guide surface 24a and a stop surface 24b as shown in Figs. 3, 5. From an inspection of Fig. 5, it will be noted that a radial line extending through armature 10 as indicated by the dot-dash line will intersect a guide surface 17a of outer guide member 14 at an oblique angle adjacent the apex of the tooth. Furthermore, it will be seen that a radial line extending through the root of a pair of outer guide teeth 17 will intersect a guide surface 24a at an oblique angle adjacent the apex of a tooth 24.

The magnetic circuit of the device comprises casing 1 ring 16 and armature '10. Any suitable electrical pulse source may be used to deliver pulses to coil 7 thereby linking the magnetic circuit. Such means is diagrammatical ly represented in Fig. 1 by a battery 25, switch 26 and cam 27 which upon rotation is adapted to make and break switch 26.

When the magnetic circuit. is linked upon delivery of a pulse to coil 7, armature 10 will be moved radially outward in the path indicated by the dot-dash line of Fig. 5. This path of movement will engage armature 10 with a guide surface at an oblique angle as indicated by the dot-dash position a and said armature will then be deflected and guided at an obtuse angle with respect to its initial path of movement until arrested from further movement by engagement with a stop face 17b of the next successive tooth 17'as indicated by the dot-dash position 10b. The above may appropriately be considered an initial operation in consideration of the following and terminal operation upon termination of the magnetizing pulse.

Upon termination of the magnetizing pulse, armature 10 will be moved radially inward by its spring bias from the dot-dash position 10b in the dot-dash path as indicated in Fig. 5. This inward radial movement of armature 10 will bring it into engagement with a guide surface 24a of inner guide member at an oblique angle as indicated by the dot-dashposition 10c. Armature 10 will thereupon be deflected to an obtuse course of movement with respect to its inward radial path and will be finally arrested from further movement by engagement with a stop face 24b of the next adjacent guide tooth 24 as indicated by the dot-dash position 10d.

The above sequence of operations will be repeated in response to delivery of each pulse to coil 7. It will be seen that the outward movement of armature 10 will be guided in an initial step clockwise toward the position 10d and that the inward movement will be guided further clockwise in a terminal step to complete the indexing operation.

The utilities of the stepping device will be apparent to those skilled in the art. For example, guide teeth 17 or teeth 24 may function as commutator segments with armature 10 as a common contact member, or the armature could be operable in conjunction with other switching or control devices.

A number of modifications of the invention are possible without departing from its principles of operation. For example, armature wire 10 could be resiliently biased radially outward into normal engagement with guide member 14 instead of inwardly with guide member 15 as disclosed and moved electromagnetically inwardly to engage member 15. In this instance, the armature would be mounted for axial rotation at its right end instead of fixed by clamping member 11 as disclosed. Furthermore, the armature could be biased by independent spring means instead of by inherent resiliency. The invention therefore is to be restricted only as necessitated by the appended claims.

I claim:

I. An electromagnetic stepping device comprising: an armature mounted for circumferential movement, for radial movement and for a composite of both movements with respect to the axis of a circumferential series of location points, and resiliently biased against movement from any one of said points; means for locating said armature at any one of said points; a first guide means having an annular series of internal guide surfaces concentrically located with respect to said location points; a second guide means having a peripheral series of external guide surfaces concentrically located and radially spaced with respect to said internal guide surfaces, and complementally operable respectively therewith; a magnetic circuit for moving said armature from any one of said location points; means for linking said circuit in response to an electrical pulse to move said armature from one of said location points into engagement with one of said guide surfaces for guiding in an initial step of movement toward a next successive location point and upon termination of said pulse for movement by its spring bias into engagement with the complementally operable guide surface for guiding in a terminal step of movement to said next successive location point.

2. An electromagnetic stepping device according to claim 1: said armature being resiliently biased with respect to said location points in a given radial direction; each internal guide surface intersecting a radial path of movement of said armature obliquely in a given angular direction; each external guide surface intersecting a radial path of movement of said armature obliquely in the opposite angular direction; and said magnetic circuit being operable to move said armature radially against its spring bias.

3. An electromagnetic stepping device according to claim 2: said armature being resiliently biased radially inward.

4. An electromagnetic stepping device according to claim 2: said armature comprising a length of resilient magnetic material mounted at one end in axial alignment with respect to said guide surfaces and said location points; the opposite end of said armature extending between said external and internal guide surfaces.

5. An electromagnetic stepping device according to claim 4: said armature being resiliently biased radially toward a straightened position. I 6. An electromagnetic stepping device comprising: an armature mounted for radial movement, for circumferential movement and for a composite of both movements with respect to a given axis and resiliently biased in a given radial direction; a first guide member having a circumferential series of alternate terminal guide and stop surfaces concentrically located with respect to said axis, each of said terminal guide surfaces intersecting a radial path of movement of said armature obliquely in a given angular direction and extending to a terminal stop surface to provide a location point for said armature, said armature being normally located at one of said points by its radial resilient bias; a second guide member having a circumferential series of alternate initial guide and stop surfaces concentrically located with respect to said axis and radially spaced from said terminal guide and stop surfaces in the radial direction opposite to the resilient bias of said armature, each of said initial guide surfaces intersecting a radial path of movement of said armature from one of said location points obliquely in the angular direction opposite to the oblique angular direction of intersection of said terminal guide surfaces and extending to an initial stop surface to provide a stop point in one of said radial paths of movement intersected by one of said terminal guide surfaces; a magnetic circuit for moving said armature radially against its resilient bias; and means for linking said circuit in response to an electrical pulse to move said armature radially against its resilient bias from one of said location points into engagement with one of said initial guide surfaces for guiding to one of said stop points in an initial step of movement toward a next successive location point and upon termination of said pulse for movement by its spring bias radially into en gagement with one of said terminal guide surfaces for guiding to said next successive location point in a terminal step of movement.

7. An electromagnetic stepping device according to claim 6: said armature being resiliently biased radially inward toward said axis.

8. An electromagnetic stepping device according to claim 7: said armature comprising a length of magnetic material fixedly mounted adjacent one end along said axis, and resiliently biased toward a straightened axial position to normally engage one of said terminal guide surfaces at one of said location points.

9. An electromagnetic stepping device according to claim 8: said magnetic circuit comprising said armature and a cylindrical casing concentric with said axis; and said linking means comprising a solenoid coil housed in said casing and surrounding said armature.

References Cited in the file of this patent UNITED STATES PATENTS 

